


Third Law

by cosmotronic



Category: Mass Effect
Genre: F/F, Light Dom/sub, Sex Toys, Size Kink, Smut, Strap-Ons, Threesome
Language: English
Status: Completed
Published: 2016-11-04
Updated: 2016-11-04
Packaged: 2018-08-29 01:23:04
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,048
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8470258
Author URL: https://archiveofourown.org/users/cosmotronic/pseuds/cosmotronic
Summary: Samantha is surprised at their dynamic.





	

**Author's Note:**

> Nothing to worry about, it's all consensual fun.
> 
> Feedback, comments welcome.

Their relationship surprises her when she learns of it.

She's flirted awkwardly with Shepard since the start. She reckons it’s the arse that did her in; she catches herself staring at that fantastic tight arse in the CIC. It's pert and muscled, positioned perfectly in her eyeline thanks to the raised command console. She can't drag her gaze away, feels her intelligence draining from her ears as she stammers out her reports. And the physical attraction is only a small part of it. She admires Shepard, regards her with an awe that’s so close to hero worship it’s embarrassing. Especially when her mind races, desperate to impress and her mouth goes with it. Shepard bears her enthusiasm with grace and flirts back, smooth and easy. She feels special, but she knows she’s not and that the Commander must have a girl in every port and she just shouldn’t go there.

Then Ashley comes aboard and takes her breath away from their first meeting, all curves and muscles and lips that make her blush. Her body begs to be held in those strong arms, her fingers long to sift through that soft black hair. Ashley seems like the type to fall into such a touch and never hesitate to take what she wants in return, bold and demanding. Ashley would always know her own desires, her needs. The marine is dedicated and proud, pouring herself into her duty and she can’t help but wish she were the focus of those attentions, that those chocolate eyes would melt over her.

She’s crushing hard and it’s driving her crazy. She finds herself tripping over words when her commander's around and painfully silent and shy around the marine. Shepard's power and easy charisma is the drug, she knows, but Ashley is _gorgeous_. The differences in their personalities make it worse, like she's being forced in opposing directions.

She's never noticed anything but guarded tension between the two of them. She’s not completely up to speed on the history but there must be something driving a wedge between them. They fought Saren together, saved the Citadel together, they were comrades, friends. Maybe more; and that's a dangerous thought considering their positions. But now they barely interact outside of missions and briefings. Shepard stares, sometimes. There's something sad in the gaze and she wants to ask but it isn't her place.

So she is shocked but intrigued when they approach her together at the end of her shift, invite her to Shepard's cabin later that night. Something about getting it out of her system though she suspects they all have that particular itch to scratch. She doesn't think about it, doesn't question that it's them, together, asking her to join them. She just nods shyly and flees to the showers to quell the sudden heat between her legs. She debates what to wear, then decides she probably won't be wearing anything long enough for it to really matter. The elevator ride to the top deck seems to last forever, and then she is there and they are there and she feels stripped bare and mortal in the presence of gods.

Shepard reclines in a chair, lionlike. One boot rests on the low coffee table, the other flat on the floor. Her legs are slightly spread and her body is relaxed, languid. A stud at ease. She rakes her eyes over the lithe, sinewy form, lips parting involuntarily. Shepard watches her right back, the play of a smile on her lips, the eyes of a predator. Shepard’s all rough edges but there's an aura of power that permeates the room, flowing over her, around her. She's contemplated how Shepard would approach her sexual encounters; would she command her lovers, would she have to? She can't lie, she's pictured it, imagined herself falling unbidden at Shepard's knees.

She never dreamed it would be like this though, not with Ashley standing there, possessive and dominating the air, a harsh note counterpoint to Shepard's relaxed subtlety. Ashley is taller, more obviously muscled as she stands at Shepard's shoulder, all tense strength and striking beauty, such a clear alpha presence. _Shepard’s mine_ , Ashley’s body seems to say and she is shocked as she realises how little this liaison was Ashley's idea, just how persuasive Shepard must have been. She can't imagine Ashley submitting to anyone – and the marine is definitely not one to share – yet here they all are.

She wonders how they reconcile their natures. Though their goals are not disparate, they are different in their approach. Both determined and efficient as they fight to protect, both needing to be strong every second of every day, but Ashley is rigid, ethically unwavering where Shepard is loose, a renegade. The same shape but mirrored, impossible to fit together without one bending, like trying to hold your own hand. Shepard was Ashley's superior, back on the first Normandy, but she discounts the power play immediately. She knows that rank would always be left at the door. Has to be, how else could she be here tonight? So that leaves trust and surrender and pure physicality. They have nothing to prove but would they, could they ever lose control, open themselves to the feeling, their feelings, without a fight?

She imagines it, the wrestling for superiority. They’d pin each other down. A thigh forced between the other's legs, or a plundering hand between them. Maybe they’d scratch, or bite. She thinks Shepard would end up on top, would hold the younger soldier down and take her. Not to break her – Ashley would never allow it – but to reward her, to please her demands. It would be heated, passionate and painfully intense. She endures a jump of nervousness amidst the growing arousal in her gut; rough sex was never her scene and she is unsure if they know any other way.

There's no time to explore the thought further. Right now all their attention, the sheer weight of their desire, is directed at her and she feels small. Shepard rises and stalks closer, invading her space.

“Traynor.”

It's not even a question. A low, throaty statement of intent growled into the thick air. Ashley's stepped closer too, circling behind her, she can hear her heavy breathing, feel the moist exhalations on the back of her neck. They don't touch her, they wait an eternal second, allowing her the tiniest hesitation.

She nods and then she is trapped between them. Warmth and power and solid muscle. She melts into the hard bodies, water between two rocks. Shepard's lips are hot on hers, fingers are slipping under her shirt, stroking the curve of her hips and pulling them close to Shepard's own. She can feel the hard ridge there, pressing her through layers of cloth and she moans wantonly into Shepard's mouth. Ashley nips at her shoulder from behind, tonguing her neck, squeezing her breasts. She leans into the touches, desire pooling at her core. She wants this, desperately.

Ashley is the one to strip her; she barely catches the marine’s low, questioning “Shepard?” and the equally small nod of agreement. It seems to confirm her earlier appraisal of their relationship: commanding but never controlling.

Her clothes are removed quickly, efficiently. She's not embarrassed when her breasts are freed to the air, to Shepard's lust-blown gaze. She doesn't blush when her soaked underwear is pulled down her trembling legs.

Ashley strips as well - oh _damn_ , that body - then pulls Shepard’s shirt off. For a horrible moment she thinks she has been forgotten as the pair kiss and fondle, hands roaming over exposed skin. Then Shepard's fingers are caressing Ashley's cheek, turning their faces, shifting their attention with a nod in her direction.

Ashley leads her to the bed, makes her lie back. She is so excited, she cannot help the arch of her spine or the spread of her legs. Now Ashley's strong arms are on her shoulders, holding her down. Shepard's hands are tight on her thighs, pulling them wider, opening her eagerness to her view. The temperature in the cabin seems to soar. Ashley is kneeling behind and leaning slightly over her, panting, mouth open; she must be drowning in the sight of her lover about to fuck another woman. And it is a _magnificent_ sight, Shepard standing statuesque and glorious between her legs. Naked torso gleaming with sweat and etched by shadows, tousled hair catching highlights from the low level lightning. A bead of perspiration runs a course through a valley of firm breasts and across sculpted abdominal plains. There are scars, so many scars, she hadn't realised how many, and she finds herself irresistibly turned on by the show of strength.

Shepard's still wearing her boots and fatigue pants, open at the fly to reveal the bulging cock within. It's purple. It would be ridiculous if it weren't so darn hot. It's at her core now, blunt head grazing her clit, then nudging at her slick entrance. She can tell it's big, bigger than the toys she uses on herself, but she feels no uncertainty.

She wonders if Shepard wears a cock for Ashley; from Ashley's small breathy reactions she determines it is likely. She tries to picture how they would do it. Like this, Shepard spreading Ashley wide and plunging deep within? Perhaps on all fours with Shepard palming Ashley's hips or fisting her hair? Or would Ashley be on top, riding Shepard hard? The montage of vivid imagery encourages a sudden rush of arousal, spilling out to coat the tip of the shaft and then coherent thought is ripped from her as Shepard pushes forward.

She gasps. It feels _huge_ , so thick and it's been far too long and she can't help but tense a little. Shepard pauses, waits for her to adjust. The firm grip on her thighs never lessens, the pressure does not ease; Shepard knows she only needs a moment. Ashley's thumbs are rubbing soothing circles on her shoulders, willing her to relax and she melts into the touch. She sighs, not quite a moan, and feels her body opening up, giving in to the sensations and the fullness.

Shepard withdraws until only the wide head of the toy remains inside, an agonising tease, then presses back in again, slow and sure. The slide is easier, slick wetness flowing freely now, still she knows Shepard isn't yet all the way inside her. She groans, an edge of frustration and neediness to the sound. This is no time for being so damn considerate and she stretches her arm towards Shepard's hips, wanting to grasp her, pull her deeper. She can't reach and her fingers claw ineffectually at the air. Shepard understands, though, and begins to move with building intensity, their flesh meeting with every stroke.

She moans, a throaty gasp torn from her each time Shepard bottoms out. She bites her lip to muffle the noise. She has a wild thought that maybe she is dreaming, that crying out too loudly would shatter the fantasy. Shepard would ghost away, Ashley would fade and she would be left alone in her bunk, fingers buried in her wet pussy, screaming into her pillow.

But it's real, oh _fuck_ is it real. The thickness of Shepard's cock is putting wonderful pressure on that perfect spot and the stretch inside her is intense, almost uncomfortable. The drag along her inner walls, across the tight ring of her opening as Shepard thrusts firm and forceful, it is a delicious agony. Her peak is near, she's so close to tumbling over that precipice. But it's not quite enough, she can't possibly come like this. She moves her hand slightly, fingers itching towards her centre. The briefest touch on her clit would be enough to tip her over and she sobs when Ashley captures her hand and pulls it away.

“No.”

Ashley shifts the steady grip to hold both her arms by her sides and she is helpless. The position allows Ashley's heavy breasts to hang over her and she aches to taste them, to reach out with her lips and suck a dusky nipple into her mouth, to tease with her tongue and nip with her teeth, to punish Ashley for denying her. It's only a wish, the tiniest rebellion she can muster and it is swept away as Shepard suddenly increases the pace and power of her movements, fucking her into the bed.

She cries out her pleasure now, incoherent and unchecked. Shepard is a restrained animal, forceful yet precise and controlled. So skilled and... _trained_ , she realises through the haze of bliss. Ashley has her lover well-practised; allows Shepard to dominate completely, physically. Lets her exert her strength but only to meet a singular demand, a focused intensity meant to bring her partner the greatest possible pleasure. Shepard is a wild beast, broken and bridled for service. It's an intensely powerful, erotic moment of clarity and she feels herself climbing close to the edge once more.

She wonders how long Shepard can possibly last like this. Her thrusts are relentless, she must be tiring and the toy has to be creating incredible friction within her as well. Indeed, there's a tiny quiver to her movements now, small growling gasps escaping her lips. She is holding back, waiting for something more.

“Ash.”

And there it is. Ashley moves forward instantly, kneeling over her, her arousal swollen and obvious, open and ready. She almost whimpers in anticipation of tasting this strong, beautiful, lustful woman, making her writhe under her touch. She's good at this, she knows. She knows how to twist her tongue just so, how to lick and suck and nip to elicit the greatest response. She knows how to make her lovers tremble at the knee, so she puts everything into pleasing the woman above her.

She drags her tongue across the hot flesh, enjoying the shudder as the tip brushes Ashley's clit. Good, a sensitive one. She doesn't hesitate, knows they don't want her to hold back, so she latches her mouth over the tiny bud and sucks hard, once. Ashley grinds down, forceful and a little demanding. She doesn't want this to end too soon so she uses what is left of her resolve to switch her attentions to the entrance below, thrusting her tongue up and around just inside the tight core. She withdraws to flick up and over Ashley's clit again, then back inside, over and over. The wetness on her tongue is flowing freely now, Ashley's lust a delicious reward for her efforts and she laps at it, greedy.

Being between and beneath their bodies like this, trapped beneath them, the instrument of their pleasure and a precious idol to be worshipped, it is almost more than she can believe. She's a goddess amongst them. She feels blessed by their trust, and they are trusting her so completely, trusting her to take what they offer and not judge. She thinks that's a greater leap than the trust she places in them as they use her body, as they touch her and fuck her and enjoy her reciprocations.

Ashley shifts on her knees after a while, leaning forward. The angle of the thrusts between her legs changes slightly as well, becomes shallower and she knows they are leaning together, kissing over her body.

Shepard’s movements are becoming more erratic, thighs trembling with exertion and voice almost breathless when she murmurs a single word against her lover’s mouth.

“Please.”

Ashley’s climax is like a fit of rapture and the intensity takes her a little by surprise. She has to reach up to steady the hips above her as proud, controlled Ashley comes undone so completely, thighs clamping down on her head, shaking and mewling. There's a noise, halfway between a scream and a sob, sounding staccato from Ashley's mouth and she feels the smallest hint of smugness as she continues to lick at the swollen flesh above her. She doesn’t come anything like that hard and it’s rare she finds another able to reach such heights.

Ashley's lover is only a half-moment behind, stamina and willpower finally failing. Shepard’s hips are pressed tight against her, she’s fully inside when she stills her thrusts and comes with a deep groan and a full-body convulsion. Shepard’s fingers are like tiny vices on her flesh, digging, bruising as she grinds deeper into her and shakes above her.

The euphoria of their twin orgasms washes over her. They have thrown themselves completely into this moment and she feels herself being swept along by the rushing tide. Even in the grip of her own shuddering climax Shepard has the decency to rub a calloused thumb over her swollen clit. It's enough and she comes along with them, her body arching into them. She screams into Ashley’s trembling flesh, screams herself hoarse and feels herself flowing out about Shepard, hot come pulsing to soak the sheets beneath her. The relief is immense, the sensation liquid ecstasy and she can't resist a hysterical, breathless laugh as she comes down – it's never happened like _that_ before.

She barely registers Shepard slipping out of her or Ashley rising off her. One of them strokes her cheek softly, brushes sweaty hair back from her face. She can’t tell which one kisses her sticky lips, it doesn’t matter. She lies there, stunned and aching and content to drift in the afterglow.

Time ticks along and she slowly falls back into reality. She looks, sees them entwined together on the other side of the bed. Shepard is naked now and Ashley has made it into her lover's lap. She doesn't know if Shepard is inside Ashley; their embrace is too close to tell. She watches them as they kiss, slow and sensual and beautiful. There's love in their eyes and comfort in their touches and she suddenly feels a privileged outsider. How few have seen this secret bond, how fewer still would understand it.

They’ll look after her, she knows they will; neither are the sort to use for pleasure and throw away. But in this moment they are only for each other, two storms swirling in subtle synchronicity. Their relationship makes perfect sense, she realises. Their dynamic surprises her and their secret saddens her, but it makes sense.

**Author's Note:**

> That was naughty of me. I actually like Traynor, she's sweet. But in my head she's kinky too and she'd love to be topped by one or both of our tough soldier gals. Mm-hmm.
> 
> Also some hints of how Shep and Ash could work as two potential doms. Shepard would be a sweet, _sweet_ service top, even though subby ain't really her style. Ash is clearly possessive, direct and probably a proper frisky power bottom (hate that label, but _damn_ ) when they're doing the dirty. Anyway, enough of my ramblings, got some ideas in me exploring that dynamic, but this beastie had to be let out first.


End file.
